Linear sweep generator



March 9, 1954 A. FONG 2,671,858

LINEAR SWEEP GENERATOR Filed April s. 1946 J INVENTOR ARTHUR FONG F IG. 2

ATTORNEY Patented Mar. 9,, 954 I v r 2,671,858

2,671,858 LINEAR swear GENERATOR Arthur Fonz, Los Angeles, Calif. Application April 3; 1946, Serial No. 659,187 1 Claim. (01. 25o s6) UNITED STATES PATENT OFFICE This invention relates to sweep generators and during the period of time required for most sweep more particularly to an improved sweep generator voltage applications. for producing a very linear sweep. Figure 2 is a schematic diagram of a typical In cathode ray oscilloscope presentation of circuit using a combination resistance-capacishort duration signals it is imperative that a 5 tance and inductance-capacitance charging cirvery linear sweep voltage be applied to the horicult to generate a linear sweep voltage Inductzcntal deflecting plate in order that an undisance 50, resistance 5| and capacitance 52 make u and inductance-capacitance resonance circuits mg arrangement for the generation of a sawbeen obtained In portable test equipment where resistances 55 and Transformer 51 provides reduction in weight and bu are prime factors, 10 an inductive feedback circuit between the plate it is desirable to provide a circuit that will genand the grid of electron tube 54 1 h a fixed erate a very linear sweep voltage with a minimum bias on electron tube 54 it is necessary that the of circuit components. plate potential be of suflicient value to overcome The primary object of the present invention is t is bias before the tube W111 conduct Electron to provide a linear sweep voltage generator. tube 54 must necessarily be ofi during the chargvoltage wave that is linear, with a minimum of ductance 50 and resistance 5| toward the value of component parts. voltage at point 58. As some point on the A further object of the present invention is to charging curve, the potential on condenser 52 field test equipment, be high enough to cause the tube to conduct As The foregoing and other objects will become the current builds up through the plate winding apparent from the detailed description and the of transformer 51, the potential on the grid of accompanying drawings in which: tube 54 is caused to rise by the action of trans- Fig. 2 is a schematic diagram of a typical cir- 52 is quickly discharged toward the potential excuit employing the superposition principle illusisting on the cathode of tube 54. When the curtrated in Fig. 1. rent no longer is increasing through the plate ring to the drawings, and more particuwindings of transformer 51, the potential on the Refer larly to Fig. 1, the elementary circuit consisting grid of tube 54 is driven down and the tube cuts voltage at terminal l2, and condenser l3, will prois apparent, then that a self synchronous sawof positive voltage at terminal l8, and condenser 5 will be apparent to those skilled in the art that and connected to a source of positive voltage at ing arrangement utilizing the above described cir- 29 is momentarily closed and reopened. With tion. A triggering voltage schematically illusproper selection of inductance 23, resistance 24, trated by the legend Trigger" applied inductively and capacitance 26, curve 28 will be very linear by means of winding 62 to the grid winding or transformer 51 could be used to synchronize the sawtooth voltage output in time relation with other circuits. The foregoing description of switching methods used with the invention should not be construed as a definition oi the invention, but is considered illustrative of one form the invention may take.

What is claimed is:

A linear sweep voltage generator capable of generating a cyclicly recurring sawtooth volt: age comprising, an inductance; a resistance, said inductance connected in parallel with said resistance, an adjustable source of positive voltage, one end of said parallel resistanoc inductance combination connection to said adjustable source of positive voltage, a condenser, said condenser connected in series with said parallel resistanceinductance combination and said adjustable source of positive voltage, an electron tube, aairl electron tube having at least an anode, a cathode an a controlgrid, a source of positive voltag a voltage divider, the cathode of said electron tube connected to said voltage divider, said voltage divider connected. to said. source of p tive oltage. a transformer, th primary winding o said trans,- formerconnected in series be een the anode of sa d electron tube and the un t on of said parallel resistancesinductance combination and said condenser, the secondary of said transformer connected between the grid 01 said electron tube and ground, the combination of said electron tube, said voltage divider, and said transformer serving as a switch, said switch opening and closing in correct time sequence with the charging period of said inductance resistance and condenser, said adjustable source of positive voltage determining the period of said sawtooth voltage obtained at the junction of said condenser and said parallel resistance-inductance combination.

' ARTHUR FONG.

References Cited in the file of this patent UNITE STATES PATENTS Number Name Date 2,085,402 Vance June 29, 193'! 2,096,982 Schlesinger Oct. 26, 1937 2,105,17 Barthelemy Jan. 11, 1938 2,148,096 Banks Feb. 21, 1939 2,188,653 Faudell et al. ,Jan. 30, 1940 2,413,063 Miller Dec. 24, 1946 2,438,845 Dodds -0... Mar. 30, 1948 2,562,925 Lader Aug. '1, 1951 FQREIGN PATENTS Number Country Date 434,326 Great Britain Aug. 29, 1935 

